Imaging of Vascular Smooth Muscle Cells with Soft X-Ray Spectromicroscopy

Abstract

Using X-ray microscopy and spectromicroscopy, vascular smooth muscle cells~VSMCs! were imaged, prepared without using additional embedding material or staining, but by applying simple, noncryo fixation techniques. The cells were imaged with a compact source transmission X-ray microscope and a scanning transmission X-ray microscope~STXM!. With the STXM, spectromicroscopy was performed at the C K-edge and the Ca L III,II -edges. VSMCs were chosen because of their high amount of actin stress fibers, so that the actin cytoskeleton should be visible. Other parts of the cell, such as the nucleus and organelles, were also identified from the micrographs. Both in the spectra and the images, the effects of the different preparation procedures were observable. Furthermore, Ca hotspots were detected and their density is determined.

PVP-coated, negatively charged silver nanoparticles: A multi-center study of their physicochemical characteristics, cell culture and in vivo experiments

“…25 µg mL −1 of O 2 -free aqueous dispersions with silver nanoparticles were incubated for 24 h with human mesenchymal stem cells (hMSC) and HaCaT cells (human keratinocytes) grown on collagen-coated Si 3 N 4 -membranes [75]. After incubation the cells were dried and fixed [75].…”

“…In addition, even thick (up to 10 µm) and wet samples can be studied. In spite of these advantages, the number of available setups is limited, so that STXM has only been applied to a small number of biological or biomedical samples in the past, including the investigation of local morphological changes in cells [75]. …”

“…For this purpose, hMSC were grown on collagen-coated Si 3 N 4 -membranes and incubated for 24 h with O 2 -free aqueous dispersions of silver particles ( c = 25 µg mL −1 ). After incubation, the loaded cells were dried and fixed [75]. Subsequently, STXM-images were recorded at the PolLux scanning transmission soft X-ray microscopy (STXM) microscope at the Swiss Light Source in the water window at 510 eV below the O K-edge, where the contrast for organic material is optimal.…”

Scanning X-Ray Nanodiffraction on Living Eukaryotic Cells in Microfluidic Environments

“…In the soft x-ray regime, imaging of fixed-hydrated and (initially) living eukaryotic cells using scanning transmission x-ray microscopy and spectromicroscopy have been demonstrated [17]. Cellular organelles could be identified and near edge x-ray absorption fine structure spectra were recorded, yielding different calcium concentrations for different cellular regions.…”

Soft x-ray spectromicroscopy of environmental and biological samples

“…To prevent chemical changes and enable simple handling, fixing techniques are usually avoided for the preparation of environmental samples. Here, the effect of non-invasive sample preparation and chemical fixation on VSMCs is investigated [168]. VSMCs were selected because of their high amount of actin, a basic protein of the cytoskeleton.…”